Bioequivalence, Food-Effect Assessment and Exploratory IVIVC of Two Extended-Release Tamsulosin 0.4 mg Formulations in Healthy Mexican Subjects

Background/Objectives: Tamsulosin extended-release (ER) formulations minimize peak-related vasodilatory adverse events in benign prostatic hyperplasia (BPH) treatment. This study assessed the pharmacokinetics and bioequivalence of a generic tamsulosin 0.4 mg ER formulation against the innovator under fasting and fed conditions. Methods: Two randomized, open-label, four-period crossover, single-dose trials were conducted in healthy Mexican males. Subjects received treatment following a 10 h fast or a high-fat meal, with a 7-day washout. Plasma tamsulosin was quantified over 72 h via LC-MS/MS. An exploratory in vitro–in vivo correlation (IVIVC) analysis was also performed. Results: Analyses included 32 (fasting) and 58 (fed) subjects. In both states, 90% confidence intervals for Cmax, AUC0-t, and AUC0-∞ geometric mean ratios fell entirely within the 80.00–125.00% bioequivalence limits. The formulations showed comparable dissolution (f2 = 92.47), with numerical deconvolution proving most predictive in exploratory IVIVC. Notably, the pharmacokinetic profile of the test formulation was consistent with maintained controlled drug release under both dietary conditions and showed no pharmacokinetic evidence of food-induced dose dumping. Both formulations were well-tolerated; all adverse events were mild, with no clinically significant orthostatic hypotension observed. Conclusions: The generic tamsulosin 0.4 mg ER formulation is bioequivalent to the reference product in both fasting and fed states. Its structural robustness prevents dose dumping, ensuring a favorable hemodynamic safety profile. Comparable dissolution and IVIVC findings further support their reliability in vivo performance and therapeutic interchangeability. ClinicalTrials.gov identifiers: NCT07698288 and NCT07698275.